An LED lighting lamp rapidly replaces lighting apparatus that uses conventional light sources, such as a fluorescent lamp and an electric lamp, owing to its advantages of high energy efficiency and a long lifespan. An LED element used in the LED lighting lamp has advantages, such as the amount of emission heat smaller than that of a conventional lighting light source, low consumption power, a long lifespan, and a shock-resistance property. Furthermore, the LED element is advantageous in that it does not generate environment pollutions because mercury or gas for discharge is not used like in a fluorescent lamp in its manufacture process.
If a proper power and heat dissipation means are provided, an LED element can maintain a turn-on state without a loss although it is used for ten thousand hours or more. The light outputs of all light sources are gradually reduced over time. A person does not feel a reduction of the light output up to 80% of an initial luminous intensity. If an evaluation is performed based on the above, a lifespan for lighting of an LED element is expected to be forty thousand to fifty thousand hours or more. Accordingly, the LED element can be said to be a light source having a very long lifespan as compared with an electric lamp of 1,500 hours and a fluorescent lamp of ten thousand hours.
If a driving current is increased in an LED element in order to obtain a high brightness, high output, and economic light source for lighting, however, most of electrical energy is converted into heat and the joint portions of the LED elements become a high temperature state because a power loss in the LED elements is increased. The LED element is characterized in that if temperature of the joint portion rises although a current is constant, light output and light efficiency are deteriorated and an operation lifespan is also reduced. Accordingly, in order to improve lighting performance and an operation lifespan, it is necessary to discharge heat, generated from the joint portions of the LED elements, externally as soon as possible.
In general, an LED lighting lamp of an electric bulb type, having a small size and a small internal space, has a structural disadvantage in externally discharging heat generated from LED elements as compared with lighting of other forms. Accordingly, to increase the light output by mounting a large number of LED elements on a lighting lamp of an electric bulb type or a compact type has a limit to a mounting area and a heat dissipation area. Accordingly, there are problems in that it is difficult to obtain a lighting light source of high brightness and light from the LED elements, that is, light sources, is changed and the lifespan of the LED elements is reduced because heat is easily accumulated within the lighting lamp when the lighting lamp is mounted on lighting apparatus.
Furthermore, in a common LED lighting lamp, a light-emission unit was constructed by arranging high-brightness LED elements in the front surface of a heat dissipation frame in which a plurality of cooling pins is formed and the lighting lamp was fabricated by covering the light-emission unit with a milk-white diffusion cover in order to reduce dazzling. However, this method is problematic in that there is a great luminance difference at the time of lighting because the backlight of the light-emission unit is narrowly formed in all directions, luminance is low due to a great light loss resulting from the dark milk-white diffusion cover, an the lifespan of the lamp of the LED element is reduced because heat is also accumulated within the diffusion cover.
Furthermore, the mounting area is limited because a circuit board in which a plurality of LED elements is arranged is mounted on the front of the heat dissipation frame, which makes it difficult to dispose a large number of LED elements. For this reason, in order to obtain a large amount of light using a limited number of LED elements, expensive and high-brightness LED elements must be used or the size of the heat dissipation frame must be further increased. As a result, there are problems in that the lighting lamp becomes heavy and bulky and it is difficult to popularize the lighting lamp due to a high price result from a high manufacture cost.
Accordingly, in order to greatly expand power-saving and eco-friendly LED lighting environment by replacing the existing electric lamp and compact type fluorescent lamp, the improvement of light efficiency of an LED lighting lamp, a wide backlight condition without dazzling, and lighter, efficient, and economic heat dissipation means must be prepared.